Automatic rhythm instrument with cycle-end termination circuit

ABSTRACT

An automatic rhythm instrument is provided with a rhythm termination circuit which keeps the rhythm pattern pulse generator operating even after the stop switch is manipulated and stops keeping it operating upon detecting the end of the rhythm cycle, thus stopping the automatic rhythm performance upon completion of the full rhythm cycle. On this instrument, the player does not have to manipulate the stop switch at the exact end of the rhythm cycle, but has only to manipulate it at any time within the last rhythm cycle and the instrument keeps on the performance until it comes to the final end of the rhythm cycle and stops.

United States Patent [151 3,646,242 Okamoto Feb. 29, 1972 [54] AUTOMATIC RHYTHM INSTRUMENT Y 3,478,633 ll/1969 Mallett ..84/1.03- WITH CYCLE-END TERMINATION 3,493,667 2/1970 CampbelL. ...84/1.03 CIRQUIT 3,499,091 3/1970 Bunger ..84/l.03

[72] Inventor: Eisaku Okamoto, Hamakita, Japan Primary ExamineF-Laramie E. Askin Assistant Examiner-Stanley J. Witkowski [73] Assignee. Nippon Gakki Setzo Kabushiki Kaisha, I Atwmey Kemon, Palmer & Estabrook Shizuoka-ken, Japan [22] Filed: Mar. 15, 1971 [57] ABSTRACT [21] Appl. No.: 124,252 An automatic rhythm instrument is provided with a rhythm 4 termination circuit which keeps the rhythm pattern pulse generator operating even after the stop switch is manipulated [30] Fomgn Apphmmm Prmmy Data and stops keeping it operating upon detecting the end of the Mar. 16, 1970 Japan ..45/2162O rhythm cycle, thus stopping the automatic rhythm performance upon completion of the full rhythm cycle. On this [52] US. Cl ..84/l.03, 84/1.24 in r m nt, th play r o not have to manipulate the stop [51] Int. Cl ..Gl0h 5/06,Gl0h 1/00 Switch at the exact end of the rhythm cycle, but has only to [58] Field of Search ..84/1 .01 1.03, 1.17, 1.24, manipulate it at any time within the last rhythm cycle and the 84/DIG. ll, 22 instrument keeps on the performance until it comes to the final end of the rhythm cycle and stops. [56] References Cited 3 Claims, 9 Drawlng Figures UNITED STATES PATENTS 3,247,309 4/1966 Campbell .84/1 17 21 23 S S RHYTHM SOUND KEYERS SOURCES 22 l. a J CLOCK PULSE COUNTER QjgE PATTERN GENERATOR CHAIN ENCODER RHYTHM TERMINATION CIRCUIT Patented Feb. 29, 1972 R 3,646,242

2 Sheets-Sheet 1 F G. 1' PRIOR ART 8 S RHYTHM SOUND KEYERS SOURCES 12 I 1 CLOCK PULSE COUNTER EU QQ PATTERN GENERATOR CHAIN ENCODER 2' RHYTHM SOUND KEYERS, SOURCES T I L CLOCK PULSE COUNTER UE TE PATTERN J GENERATOR CHAIN ENCODER Y 3 f s 25 2 W v 27 I RHYTHM J TERMINATION CIRCUIT 24 s INVENTOR. (3/) K (1L. 0 1 /11, r, 'l 0 AUTOMATIC RHYTHM INSTRUMENT WITH CYCLE- END TERMINATION CIRCUIT BACKGROUND OF THE INVENTION A prior art device of this nature whose block diagram is illustrated in FIG. 1 is arranged such that predetermined rhythm sounds selected from the various sounds of percussion instruments, or the ordinary tones of chord or bass sounds, or a combinationthereof, generated by rhythm sound sources 11 are derived via keyers 13 triggered by selected rhythm pattern pulses from a rhythm pattern pulse generator 12. The rhythm pattern pulse generator 12 comprises a normally open switch l4 manipulated by the player for rendering the device operative and inoperative, a clock pulse generator 15 for generating a basic c'lock pulse having a frequency corresponding to the smallest beat unit (e.g., a quaver) of the rhythm performance, a counter chain 16 including frequency dividers arranged in plural stages and cascade connected to the generator 15, and a rhythm pattern pulse encoder 17 for generating a set of timing pulse trains representing a desired rhythm pattern selected from plural sets of timing pulse trains or rhythm patterns such as the march, rumba, tango and samba, on the basis of a predetermined AND logic combination of the ZERO o r ONE outputs from the counters 16 in their respective stages, thus providing automatic performance of such a rhythm as the repetition of a certain pattern cycle.

In the device of the above-described construction, the switch 14 must be operated at an exact time when the rhythm performance is to be terminated. Failure of proper operation will result in incomplete performance of the music.

The operation of the switch 14 thus requires greatly delicate timing control which not only requires high skill, but also i tends to a nonnegligible heavy defect obstructive to the multiplicity of performance especially when the device is to be used in combination with an electronic musical instrument 1 such as an electronic organ on which the player is required to use full of his hands and feet.

SUM RX PF .155. NYEEIIQN; W

Accordingly, the object of theinvention is to provide an automatic rhythm instrument in which the rhythm performance can be continued always to the end of the selected rhythm cycle even if the stop switch is manipulated halfway in the rhythm cycle, whereby desired rhythm performance can be easily made without need of high skill and the multiplicity in the player's simultaneous operation in the case of other musical instrument, such as an electronic instrument, being combinedly used can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic circuit diagram of a conventional automatic rhythm instrument;

FIG. 2 is a similar diagram illustrating one embodiment of the instrument according to this invention;

FIG. 3 is a concrete circuit diagram of the clock pulse generator, counter chain and rhythm termination circuit shown in FIG. 2; and

FIGS. 4A to 4F are waveform charts showing the operating waveforms derived from the circuit portions of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 2, various percussion instrument (e.g., cymbals, maracas, drum, etc.) sounds, or the ordinary tones of chord or bass sounds or a combination thereof, which are produced by rhythm sound sources 21 are derived via respective keyers 23 triggered by a selected set of rhythm pattern pulses from. a rhythm pattern pulse generator 22. The rhythm pattern pulse generator 22 comprises a normally open switch 24 manipulated by the player at the time of start and stop of the performance to render the instrument operative and inoperative and which function will be described in detail hereinafter, a clock pulse generator 25 for generating a basic clock pulse having a frequency corresponding to the smallest beat unit (e.g., a quaver or a semiquaver) of the rhythm, frequency dividers or a counter chain 26 cascade connected to the generator 25 for counting down submultiples of the frequency of signals from the generator 25, and a rhythm pattern pulse encoder 27 for selectively deriving various sets of rhythm pattern pulses (each set including rhythm pattern pulses for respective rhythm sounds and representing as a combination thereof each one of the rhythm performances on the basis of a preset AND logic combination of the ZERO and ONE outputs from the respective stages of the counter chain 26, said rhythm performances being, for example, the march, rumba, tango, samba, waltz, and bossa nova and each consisting of the repetition of a certain cycle of a preset different combination of the pulses.

According to this invention, regardless of timing of opening the switch 24 in the last rhythm cycle to which extent rhythm performance is desired, performance can be continued always until the end of that rhythm cycle.

This is achieved by providing a rhythm termination circuit 28 for keeping the opened switch 24 shunted by an electronic circuit until the rhythm termination circuit 28 detects the end of the rhythm cycle by effectively utilizing the outputs from the counter chain 26 as will be described later more in detail.

FIG. 3 is a circuit diagram embodying the clock pulse generator 25, the counter chain 26 and the rhythm termination circuit 28 shown in FIG. 2. The clock pulse generator 25 comprises an astable multivibrator 25a in which two transistors TR, and TR 2 areemployed. The counter chain 26a comprises plural stages, say four stages of flip-flop circuits FF,, FF FF and FF, (all binaries in this case) cascade connected in turn to the generator 25 and each of the flip-flop circuits FF, to FF, including two transistors TR and TR, (only 0 those in the first stage are designated by the references in the figure). And the rhythm termination circuit 280 comprises and AND-logic-circuit 31 using four diodes D,, D D and D, whose respective cathodes are connected to the ZERO output A ofthe first stage FF, and the each ONE output B, C and D of the remaining second to fourth stages FF, to FF, of the counter chain 26a; a differentiation circuit 32 consisting of a capacitor C, and a resistor R,; and a memory circuit ofa bistable multivibrator 33 in which two transistors TR,, and TR,, are used. In this case, the respective anodes of said diodes D, to D, are connected to a +8 power supply terminal 34 through a load resistor R and to the base of one TR,, of the two transistors included in the bistable multivibrator 33 through the differentiation circuit 32. The emitters of the two transistors TR, and TR, constituting the clock pulse generator 25a and the emitters of the corresponding ones included in each group of the paired transistors TR and TR, of the cascade connected flip-flop circuits FF, FF, constituting binary counter chain 26 are directly grounded, whereas the emitters of the remaining ones included in each group of the paired transistors TR, and TR, are jointly connected to the collector of the one transistor TR,, grounded via the switch 24 for resetting the counter.

Where, in the aforementioned circuit arrangement, the switch 24 is kept open under no rhythm performance, the other transistor TR,, of the bistable multivibrator 33 remains conductive, while the one transistor TR,, remains nonconductive. For the purpose of the invention, the multivibrator 33 is so designed in advance as to reverse the above-mentioned condition when the switch is closed, that is, to shunt the one transistor TR,, and cause the other transistor TR,, to become inoperative.

Accordingly, the flip-flop circuits FF, to FF, constituting each two half designed in the same way and the binary counter chain 260 remain deenergized.

Upon the closing operation of the switch 24, however, the bistable multivibrator 33 presents the above-mentioned reversed condition, that is, where the other transistor 'IR becomes nonconductive.

As a result, the emitters of the transistors constituting each half of the flip-flop circuits included in the binary counter chain 260 are grounded through the switch 24 to render the flip-flop circuits energized, thereby being capable of counting operation and in turn the rhythm performances.

Thus, the condition of the flip-flop circuits FF, to FF, is reversed to cause combination pulses consisting of binary outputs obtained by successive downward frequency division of the clock pulses from the generator 25a to be drawn out of the output terminals A, B, C and D on the ONE halves of the flipflop circuits.

Referring again to FIG. 2, the timing pulse encoder 27 consists of logic circuits including, for example, the known diode matrix having plural inputs and outputs. When combination pulses from the output tegmhiais A to p on the ONE halves and the output terrninals A B, C, and D on the ZERO halves of the flip-flop circuits are supplied to the corresponding input terminals in a preset combination by the player, then there is produced from the predetermined output terminals trains of pulses constituting in combination a set of rhythm patterns selected from among those representing, for example, the rumba, march, tango, samba and waltz. The rhythm pattern pulses thus selectively obtained from the encoder 27 are applied to the respective keyers 23 to trigger them. As a result, such various percussion sounds derived from the predetermined ones of the rhythm sound sources are respectively passed through the keyers 23 to sound for the rhythm perfonnance.

In this case, the binary combination pulses A, B, C and D as shown in FIGS. 4A to 4D from the respective stages of the flipflop circuits FF, to FF, are supplied to the corresponding cathodes of the diodes D to D, constituting the AND-logiccircuit 31, which generally gives out no output, except at the last count of the counter cycle when A, B, C and D present positive states. This AND-logic-circuit 31 may not necessarily be provided separately, if the encoder 27 includes an equivalent logic circuit therein and the output therefrom is utilized.

Now, when the playing rhythm performance is wanted to be stopped, the player opens the switch 24 at any time within the intended last cycle in advance to the end of the cycle.

However, that performance is continued to the end of that rhythm cycle even after the switch 24 is opened halfway in the rhythm pattern cycle, because the transistor TR remains nonconductive and the transistor JR conductive until the binary output combination pulses A to D from the flip-flop circuits go concurrently positive and next any one goes negative.

Thus the positive goings of the binary output combination pulses A to D from the circuits FF, to FF. due to the end count of the counter cycle (i.e., rhythm pattern cycle) result in existence of an AND-output-pulse E as shown in FIG. 45 from the logic circuit 31. As a result, the AND-output-pulse E, after being converted into a differentiated waveform F as shown in FIG. 4F via the differentiation circuit 32, is applied to the base of the one transistor TR constituting a shunt memory for the switch 24. With the negative spike of the difierentiated pulse F, the transistor TR is brought into the nonconductive state, whereas the other transistor TR is brought into the conductive state, to stop the operation of the counter, thus stopping the automatic rhythm performance.

What I claim is:

1. An automatic rhythm instrument comprising: rhythm sound sources; keyers for respectively keying the outputs of said rhythm sound sources; a rhythm pattern pulse generator providing pulses of repetitions of rhythm pattern cycles for triggering said keyers, said rhythm pattern pulse generator including switch means to start and stop the operation thereof; and circuit means to permit said rhythm pattern pulse generator to keep on operating even after said switch means is made to stop it, to detect the end of the rhythm pattern cycle and to cease keeping it operating upon detection of said end.

2. An automatic rhythm instrument according to claim 1 wherein said rhythm pattern pulse generator comprises a clock pulse generator for generating a basic clock pulse having a frequency corresponding to the smallest beat unit of the rhythm, a counter chain connected to said clock pulse generator for counting down said clock pulse, and a rhythm pattern pulse encoder for combining the outputs of said counter chain to make rhythm pattern pulses.

3. An automatic rhythm instrument according to claim 2 wherein the circuit means comprises an AND logic circuit connected to said counter chain to give out an output at the counter cycle, and a bistable circuit connected to said AND logic circuit to receive the output therefrom and connected to said rhythm pattern pulse generator for rendering it operative even after said switch means is made to stop it and rendering it nonoperative upon receiving the output from said AND logic circuit. 

1. An automatic rhythm instrument comprising: rhythm sound sources; keyers for respectively keying the outputs of said rhythm sound sources; a rhythm pattern pulse generator providing pulses of repetitions of rhythm pattern cycles for triggering said keyers, said rhythm pattern pulse generator including switch means to start and stop the operation thereof; and circuit means to permit said rhythm pattern pulse generator to keep on operating even after said switch means is made to stop it, to detect the end of the rhythm pattern cycle and to cease keeping it operating upon detection of said end.
 2. An automatic rhythm instrument according to claim 1 wherein said rhythm pattern pulse generator comprises a clock pulse generator for generating a basic clock pulse having a frequency corresponding to the smallest beat unit of the rhythm, a counter chain connected to said clock pulse generator for counting down said clock pulse, and a rhythm pattern pulse encoder for combining the outputs of said counter chain to make rhythm pattern pulses.
 3. An automatic rhythm instrument according to claim 2 wherein the circuit means comprises an AND logic circuit connected to said counter chain to give out an output at the counter cycle, and a bistable circuit connected to said AND logic circuit to receive the output therefrom and connected to said rhythm pattern pulse generator for rendering it operative even after said switch means is made to stop it and rendering it nonoperative upon receiving the output from said AND logic circuit. 